Trimetallic hydrocarbon reforming process

ABSTRACT

Novel catalysts suitable for hydrorefining comprising of alumina, tin or lead and platinum and iridium; a catalyst of alumina, on which tin metal in a particular manner has been first deposited and thereafter platinum has been deposited thereon, is especially advantageous.

Weisang et al.

Engelhard, both of Le Havre, France Compagnie Francaise de Raffinage, France The portion of the term of this patent subsequent to Oct. 24, 1989, has been disclaimed.

Filed: Dec. 14, 1973 Appl. No.: 424,783

Related US. Application Data Division of Ser. No. 234,875, March 15, 1972, Pat. No. 3,822,221, which is a continuation-in-part of Ser. No. 11,325, Feb. 13, 1970, Pat. No. 3,700,588.

Assignee:

Notice:

Foreign Application Priority Data Feb. 14, 1969 France 69.03646 Mar. 24, 1971 France 71.10459 1*May 27, 1975 521 US. Cl 208/138; 208/139 51 rm. Cl C10g 35/08 [58] Field of Search 208/138, 139; 252/455 R, 252/466 PT [56] References Cited UNITED STATES PATENTS 3,554,902 1/1971 Buss 208/138 3,700,588 10/1972 Weisang et a1. i 208/139 3,718,578 2/1973 Buss et a1 208/139 Primary ExaminerDelbert E. Gantz Assistant ExaminerJames W. Hellwege Attorney, Agent, or FirmCurtis, Morris & Safford [5 7] ABSTRACT Novel catalysts suitable for hydrorefining comprising of alumina, tin or lead and platinum and iridium; a catalyst of alumina, on which tin metal in a particular manner has been first deposited and thereafter platinum has been deposited thereon, is especially advantageous.

2 Claims, 1 Drawing Figure TRIMETALLIC HYDROCARBON REFORMING PROCESS This application is a division of application Ser. No. 234,875, filed Mar. 15, 1972, now US. Pat. No. 3,822,221, issued July 2, 1974, which in turn is a continuation-in-part of application Ser. No. 11,325, filed Feb. 13, 1970, now US. Pat. No. 3,700,588, issued Oct. 24, 1972.

This invention pertains to a catalyst; more particularly, this invention pertains to a hydrorefining catalyst which represents a further nonobvious improvement and an advance over the catalysts disclosed in the above-mentioned parent application.

In reference to the parent application, the object of the latter is a catalyst formed of a support of refractory mineral oxide of a specific surface of more than m /g, and a pore volume of more than 0.1 cm /g and having acid sites, and of metals deposited on said support in free or combined form, the said catalysts being characterized by the fact that the said metals consist of:

a. 0.02 to 2 percent, and preferably 0.1 to 0.7 percent, referred to the total weight of the catalyst, of at least one metal belonging to the platinum and paladium lines in Group VIII of the Periodic Table, and

b. 0.02 to 2 percent, and preferably 0.05 to 0.6 percent, referred to the total weight of the catalyst, of at least one metal belonging to the group consisting of lead or tin or their mixtures. Additionally, it has been found that germanium is useful in place of lead and/or tin or upon addition to each, or the two, in mixtures.

The present invention relates to catalysts of the type described in the parent application comprising several metals of the platinum group or line and more particularly platinum and iridium. The inventors have noted, as a matter of fact, that these catalysts are very advantageous due to their resistance to aging, particularly when applied to the reforming of charges in the presence of hydrogen.

The preferred object of the present invention is therefore a catalyst in accordance to the parent application which, however, consists essentially of the following composition:

a. 0.02 to 2 percent, and preferably 0.1 to 0.7 percent, of platinum, referred to the total weight of catalyst; and

b. 0.02 to 2 percent, and preferably 0.1 to 0.7 percent, of iridium, referred to the total weight of catalyst; and

c. 0.02 to 2 percent, and preferably 0.05 to 0.6 percent, of tin, referred to the total weight of catalyst.

The use of this catalyst to the hydroreforming of hydrocarbon charges also constitutes an object of the present invention.

The support of the catalyst in line with the parent application should have the characteristics which are described in said parent application; in particular, the support must have sufficient specific surface, generally between 15 and 350 m /g, as well as a sufficient pore volume, generally between 0.4 and 0.8 em /g. Moreover, the support must have isomerizing sites; the latter may be created by a prior treatment of the support with an acid; a suitable acid is hydrochloric acid. If the support is treated with chlorine the catalyst has a range of chlorine content from 0.3 to 1.5 based on percent by weight of the total catalyst.

The processess for depositing metals on the support are the processes customary in the art. Nevertheless, the applicants have obtained particularly satisfactory results by using the impregnation method which consists in immersing the support in a solution containing one or more of the elements to be deposited.

The depositing of iridium does not require any particular precautions over those described in the parent application. One simple method consists in simultaneously depositing the iridium and the tin by impregnation of the support with a solution containing the two elements and then depositing the platinum.

The invention is furthermore illustrated by the following examples, which are not limitative:

EXAMPLE I An alumina in the form of beads is used, the physical properties of which are as follows:

Average radius of the beads 1.6 mm Specific surface 174 m /g Specific pore volume 0.74 cm /g Average radius of the pores A This alumina is calcined in air for 8 hours at 600C; it is then used as support for two catalysts, T and A, prepared in the following manner:

CATALYST T 10 cc are prepared of a solution containing 0.268 g of hydrated iridium chloride in hydrochloric acid (reagent purity).

This solution is diluted with water to cc and then contacted with 50 g of the calcined support. After drying and calcining, the impregnated alumina is treated for 24 hours with an 0.1 N hydrochloric acid solution which is kept in circulation. After centrifuging, the alumina is immersed in a hexachloroplatinic acid solution (H PtCl 6H O). The catalyst is dried and then calcined at 400C for 3 hours. The composition of the catalyst T (in components other than alumina), expressed in percentage of the total weight of the catalyst, is as follows:

Platinum 0.35% Iridium 0. 14% Chlorine l .4 1%

CATALYST A Platinum 0.35%

Iridium 0.14%

' Tin 0.21% 1.35%

Chlorine TEST FOR CATALYTIC ACTIVITY The catalysts T and A are subjected to the following catalytic test:

A gaseous stream of hydrogen saturated with normal heptane (by bubbling hydrogen through heptane at 20C) passes at a temperature of 520C at atmospheric pressure over 2 cm of catalyst placed in a small reacpercent by weight. The catalyst is dried and then calcined at a temperature of 400C for 4 hours. There is thus obtained a catalyst T the composition of which is as follows, i.e., in components other than alumina:

tor. The sulfur content of the normal heptane is less 5 0357 than 1 ppm, the hourly space speed of the gaseous mixture (volume of gas passing per hour over a unit Chlorine 1.50% volume of the catalyst) is equal to 80. The proportion of normal heptane in the gaseous stream introduced into the reactor is equal to 2.5 percent. The efflux of CATALYST B the reactor is analyzed by vapor-phase chromatogra- The second portion of the above two portions, B, is phy. immersed in a hydrochloric solution of stannous chlo- The results obtained with the catalysts T and A are ride and iridium chloride; the tin and iridium concenset forth in Table l in which have been entered for each trations of the solution are such that the final contents catalyst at four different time periods the respective of these two elements in the catalyst, referred to their values, data or yields, to wit: metallic form, are equal to 0.2 percent by weight. The composition of the efflux in hydrocarbons having rest of the preparation of catalyst B is identical to that o r and 68 than four Carbon atoms; described above for catalyst T There is thus obtained remaining normal heptane; a catalyst B, the composition of which is as follows, i.e., hydrocarbons having five and more than five carbon of components other than alumina:

atoms, other than the unreacted normal heptane; research octane number (R.O.N.) of the liquid efflux Platinum 035% f fthhd b h f d a ter stripping o e y rocar ons aving our an Iridium 010% less than four carbon atoms. Chlorine 1.60%

TABLE I Characteristic values Operating time of the efflux (wL /r (hours) Catalysts of the charge) 1 3 7 c,-c, 31.7 31.5 31.5 32.5 T, nC 0 0.4 0.4 08 C ther than nC 68.3 68.1 68.1 66.7 R.O.N.* 113.1 113.4 113.7 110.7 C,-C, 16.8 17.4 17.0 16.1 n 0 0 0.6 0.7 A

C (other than nC 83.2 82.6 82.4 83.2 R.O.N.* 119.8 119.8 119.0 117.6

'R.O.N Research Octane Number The analysis of the results set forth in Table I shows TEST FOR CATALYTIC ACTIVITY the advantages resulting from the use of catalyst A. The two catalysts thus prepamd are then tested in EXAMPLE 1 identical, parallel tests carried out on 100 cm of cata- 1 st under the followin o eratin conditions: An alumina 15 used in the form of extruded articles, y g p g the physical properties of which are as follows:

Hourly space velocity of liquid charge 15 Average diameter of extruded articles 1.5 mm Total Pressure in the reactor 7 bars Specific surface 190 m /g (gauge) Pore volume 051 em /g Average radius f the pores 53 A Ratio of the number of mols introduced hydrogen/charge 7 This alumina is calcined at a temperature of 600C Average temperature of the catalyst 510C for 4 hours. It is then divided into two portions.

The charge to be reformed comes from an Iraq crude CATALYST 2 55 oil; it has the following properties:

The first portion of the above two portions, T is im- Initial distillation point ASTM C mersed in a hydrochloric solution of stannous chloride End dismlafion point ASTM 142C in such amount that the final tin content of the catalyst, Density measured at 20C 0.711 referred to its metal form, is equal to 0.2 percent by 0 Mmecula" (Aplmmographs) 103 W ht Th t d t. th I d Components by volume:

erg e impregna e suppor is en p ace in a ro- P ffi hydrocarbons 70% tary evaporator; it is then dried and then calcined at Naphthene hydrocarbons 24% 600C for 2 hours Aromatic hydrocarbons 6% I Sulfur content 2 ppm 0.1 N hydrochloric acid is then caused to flow for 24 hours over the alumina supporting the tin, which is then contacted with a chloroplatinic acid solution in such concentration that the final platinum content of the catalyst, referred to its metallic form, is equal to 0.35

The increase in temperature of the catalysts, effected prior to the tests proper, is carried out in the following manner:

The catalyst is heated at a rate of 50C/hour under a pressure of pure hydrogen (7 bars, without recycling) until a temperature of 3 80C is reached. After stabilization at this temperature, the recycle compressor is Catalyst B, which contains iridium, proves to be superior in time to catalyst T which does not contain any.

placed in operation; thereupon the sulfurating of the 5 CATALYTICAL ACTIVITY AS A CONSEQUENCE catalyst is effected by passage of an amount of H S cor- OF THE SI ESET I IESKZ OF TIN responding to 500 ppm, referred to the weight of the A hydrogen. The hydrogen and the charge are then intro- In order to illustrate the surprising behavior in the duced in proportions such that the molar ratio of hymethod of depositing the catalyst components, the foldrogen/charge is equal to 7; the hydrogen is separated 0 lowing comparative catalytic tests were carried out: at the outlet of the reactor and is recycled; after stabilization of the temperature, the temperature is increased PREPARATION OF THE CATALYSTS at a rate of 50C/hour up to 510C. The test proper Alumina was used which is available in the form of then starts; the temperature is maintained at the value extruded products, the characteristics of which are as of 510C for the entire duration of the test. follows:

The results of the two tests carried out on catalysts T and B have been entered in Table II, in which there are t f h i succession; average diameter of extruded alumina l.5mm

. specific surface 190 m /g the number of hours of operation without mterruppore volume 051 m /g tion; average radius of the pores 53 A the volume of charge treated (in liters masured at 20C per kil f l This alumina was calcined for 4 hours at 600C.

the average temperature of the catalyst; the research octane number (R.O.N.) of the obtained liquid fraction, measured without addition of tetraethyl CATALYST A lead;

the yield in hydrocarbons having five and more than A batch of alumina corresponding to that which has five carbon atoms, expressed in volume referred to the just been described is immersed in a hydrochloric solucharge; tion of stannous chloride in such amount that the final the ratio of the volume of hydrogen formed (meacontent of tin in the catalyst, referred to its metallic sured in liters under normal conditions) to the volume form, is equal to 0.20 percent by weight. The impregof charge introduced (measured in liters at liquid state nated support is then placed in a rotary evaporator, at 20C); whereupon it is dried and then calcined at 600C for 2 the composition by volume of the liquid efflux. hours.

TABLE II CATALYSTS T T T. T T T B B B B B B Hrs. of operation 24 72 120 168 192 216 25 73 121 169 193 217 Volume of charge 48 I44 240 336 384 432 52 152 252 352 402 treated (k/kg) Average temp. 509 510.3 509.8 510.2 510.7 510 510.3 511.2 510 511.2 510.5 510 ("C Octane Number 103.8 99.7 94.2 91.4 90.5 87.3 103.7 100.4 98 94.2 92.1 (RON) Yield C 71) 66.4 64 68.9 74.4 75.3 78.6 66.1 66 70.9 74.2 77.7 76.7

Yield 11 formed 188 182 146 132 132 182 174 153 153 156 COMPOSITION BY VOLUME Paraffin hydro- 22 30 4] 45 47 49 23 30 37 43 45 48 carbons Naphthene 2 4 6 8 8 9 3 4 6 8 12 10 hydrocarbons Aromatic 76 66 53 47 45 42 74 66 57 49 43 42 hydrocarbons The sole FIGURE accompanying the specification consists of the two curves representing the value of the octane number of the reformate as a function of the volume of charge treated with catalysts T and B, respectively, under the conditions and with the charge described in the example.

0.1 N hydrochloric acid is then circulated forv 24 contacted with a chloroplatinic acid solution of such concentration that the final amount of platinum, referred to its metallic form, in the catalyst is equal to 0.36 percent by weight. The catalyst is dried and then In the FIGURE, X-axis represents the volume of 65 calcined at a temperature of 400C for 3 hours. In this charge treated expressed in liters/kg of catalyst and Y- axis represents octane numbers.

way there is obtained a catalyst having the following composition by way of components other than alumina:

Platinum 0367: A Tin 0.2071 Chlorine 1.39%

CATALYST T r Platinum Chlorine CATALYST T 50 grams of catalyst T, are contacted at room temperature with 125 cc of a flowing solution containing 0.190 g of dehydrated stannous chloride and 1 cc of normal nitric acid. After half-an-hour circulation, the solution no longer contains any tin.

The catalyst T obtained after drying and calcining has the following composition:

Platinum 0.38% T,, Tin 0.22% Chlorine 1.43%

CATALYST T There is available a catalyst prepared industrially from the support described above and comprising 0.35 percent platinum by weight. This catalyst is placed in a column in which there is circulated a solution of stannous chloride in such concentration and for such a period of time that the final solid contains 0.20 percent tin.

The composition of the catalyst T after drying and calcining, is as follows:

Platinum 0.35% T, Tin 0.20% Chloride 1.48%

TEST FOR CATALYTIC ACTIVITY The four catalysts prepared are subjected to the following test:

25 cc of catalyst are placed in a stainless steel reactor; a stream of pure, dry hydrogen is passed over the catalyst for 2 hours, the temperature of the catalyst being maintained at 500C and the pressure within the reactor being maintained at 7 bars. Thereupon the temperature is increased to 510C and there is then introduced the batch consisting of n-heptane with a liquid hourly space speed equal to 2 and a ratio of the number of mols of hydrogen introduced and the number of mols of n-heptane introduced equal to 5.

Samples taken from the efflux of the reactor make it possible to determine on the one hand the liquid yield per simple weighing and on the other hand the equivalent octane number of the liquid by application to the chromatographic analyses of the liquid of the ASTM mixture numbers appearing on nomographs.

The curve of decrease of the octane number as a function of the time is a straight line. The slope of this line is therefore a faithful representation of the stability of the catalyst.

In the following table there have been collected the results obtained by subjecting catalysts A, T,, T, and T to the test which has just been described.

From the above data it follows:

1. The catalysts which contain tin (A and T are superior with respect to stability and yield to those which do not contain it (T Catalyst T although it contains tin, is of a behavior inferior to T because the tin was deposited without special precautions 2. The order of the depositing of the platinum and tin affects the values of the initial octane number, the stability and the average yield, as is shown by the comparison of the results of catalysts A and T It is therefore advantageous to deposit the tin first. This was not obvious a priori, but has been discovered, and this method constitutes the best method of prepar ing the catalysts.

Without being bound by a theory on the correctness of it, it is postulated that the role of the tin is to modify the support and thus permit a more dispersed and more accessible deposit of platinum that on a support which has not been subjected to a prior deposit of tin.

What is claimed is:

1. In a process for hydroreforming hydrocarbon feed in the presence of hydrogen at low temperatures, the improvement of which comprises: feeding said hydrocarbon feed over a catalyst comprising of a support of alumina of a specific surface of more than 15 m /g, of a pore volume of more than 0.1 cm /g and having acid sites, and of metals on the said support, said metals on said catalyst support consisting essentially of:

a. 0.02 to 2 percent of platinum, referred to the total weight of the catalyst;

b. 0.02 to 2 percent of iridium, referred to the total weight of the catalyst;

c. 0.02 to 2 percent of tin, referred to the weight of the catalyst.

2. The process as defined in claim 1 and wherein said metals on said support consist essentially of:

a. 0.1 to 0.7 percent of platinum;

b. 0.1 to 0.7 percent of iridium;

c. 0.05 to 0.6 percent of tin, said weight percentages being based on the total weight of the catalyst. 

1. IN A PROCESS FOR HYDROEFORMING HYDROCARBON FEED IN THE PRESENCE OF HYDROGEN AT LOW TEMPERATURES, THE IMPROVEMENT OF WHICH COMPRISES: FEEDING SAID HYDROCARBON FEED OVER A CATALYST COMPRISING OF A SUPPORT OF ALUMINA OF A SPECIFIC SURFACE OF MORE THAN 15 M2/G, OF A PORE VOLUME OF MORE THAN 0.1 CM3/G AND HAVING ACID SITES, AND OF METALS ON THE SAID SUPPORT, SAID METAL ON SAID CATALYST SUPPORT CONSISTING ESSENTIALLY OF: A. 0.02 TO 2 PERCENT OF PLATINUM, REFERRED TO THE TOTAL WEIGHT OF THE CATALYST, B. 0.02 TO 2 PERCENT OF IRIDIUM, REFERRED TO THE TOTAL WEIGHT OF THE CATALYST, C. 0.02 TO 2 PERCENT OF TIN, REFERRED TO THE WEIGHT OF THE CATALYST.
 2. The process as defined in claim 1 and wherein said metals on said support consist essentially of: a. 0.1 to 0.7 percent of platinum; b. 0.1 to 0.7 percent of iridium; c. 0.05 to 0.6 percent of tin, said weight percentages being based on the total weight of the catalyst. 